The news, revealed to E! News by a source close to the couple, comes weeks after it was announced that the former That 70s Show costars were engaged to be married.
While the couple has not yet addressed the reports, Kunis was recently spotted attending a prenatal yoga class in Hollywood, Calif.
Kunis and Kutcher got engaged in February after one year of dating. The pair met on the set of the 1990s sitcom That 70's Show.